Psych midterm

Neuron

a nerve cell; the basic building block of the nervous system

Dendrites

a neuron's bushy, branching extensions that receive messages and conduct impulses toward the cell body

Axon

the neuron extension that passes messages through its branches to other neurons or to muscles or glands

Myelin Sheath

a fatty tissue layer segmentally encasing the axons of some neurons; enables vastly greater transmission speed as neural impulses hop from one sausage-like node to the next

Action potential

a neural impulse; a brief electrical charge that travels down an axon

Refractory Period

a period of inactivity after a neuron fires

Threshold

the level of stimulation required to trigger a neural impulse

All-or-None Response

a neuron's reaction of either firing or not firing

Synapse

the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron. The tiny gap at this junction is called the synaptic gap or synaptic cleft

Neurotransmitters

chemical messengers that cross the synaptic gaps between neurons. When released by the sending neuron, neurotransmitters travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether that neuron will generate a neural impulse

Reuptake

a neurotransmitter's reabsorption by the sending neuron

Endorphins

"morphine within" - natural, opiate-like neurotransmitters linked to pain control and to pleasure

Agonist

a molecule that, by binding to a receptor site, stimulates a response

Antagonist

a molecule that, by binding to a receptor site, inhibits or blocks a response

Nervous System

the body's speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous systems

Central Nervous System

the brain and spinal cord

Peripheral Nervous System

the sensory and motor neurons that connect the central nervous system to the rest of the body

Nerves

bundled axons that form neural "cables" connecting the central nervous system with muscles, glands, and sense organs

Sensory (afferent) neurons

neurons that carry incoming information from the sensory receptors to the brain and spinal cord

Motor (efferent) neurons

neurons that carry outgoing information from the brain and spinal cord to the muscles and glands

Interneurons

neurons within the brain and spinal cord that communicate internally and intervene between the sensory inputs and motor outputs

Somatic Nervous System

the division of the periperal nervous system that controls the body's skeletal muscles.

Autonomic Nervous System

the part of the peripheral nervous system that controls the glands and the muscles of the internal organs. Its sympathetic division arouses, its parasympathetic division calms

Sympathetic Nervous System

the division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations

Parasympathetic Nervous Systems

the division of the autonomic nervous system that calms the body, conserving its energy

Reflex

a simple, automatic response to a sensory stimulus, such as the knee-jerk response

Endocrine System

the body's "slow" chemical communication system; a set of glands that secrete hormones into the bloodstream

Hormones

chemical messengers that are manufactured by the endocrine glands travel through the bloodstream and affect other tissues

Adrenal Glands

a pair of endocrine glands that sit just above the kidneys and secrete hormones that help arouse the body in times of stress

Pituitary Gland

the endocrine system's most influential gland. Under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands

Glia Cells

cells in the nervous system that support, nourish, and protect neurons

Schwann cells

Supporting cells of the peripheral nervous system responsible for the formation of myelin.

Polarization

cell at it's resting potential. negative inside, positive outside

Depolarization

The process during the action potential when sodium is rushing into the cell causing the interior to become more positive.

excitory neurotransmitters

neurotransmitters that promote action potential, causing depolarization. Some neurotransmitters are excitatory, some are inhibitory, but most can be either.

inhibitory neurotransmitters

neurotransmitters that inhibit the next cell from firing

Acetylcholine

A neurotransmitter that enables learning and memory and also triggers muscle contraction. Too little leads to alzheimers

Epinephrine

Neurotransmitter secreted by the adrenal medulla in response to stress. Also known as adrenaline.

Norepinephrine

A neurotransmitter involved in arousal, as well as in learning and mood regulation

Glutamate

A major excitatory neurotransmitter; involved in memory

GABBA

inhibitory neurotransmitter that calms you down

Dopamine

influences movement, learning, attention, and emotion. Too much leads to schiznophrenia. Too little leads to parkinsons

Serotonin

Affects mood, hunger, sleep, and arousal

Endorphins

"morphine within"--natural, opiatelike neurotransmitters linked to pain control and to pleasure.

axon terminals (terminal buttons)

Enlarged button like structures at the ends of axon branches that release neurotransmitters